System and method for reducing sound transmission

ABSTRACT

A sound transmission reduction system for use between a floor or other integer of a building construction and a suitable covering for said floor or other integer includes (I) a rigid single layer substrate of gypsum fibreboard, fibre cement, hardboard, plywood or stabilised reconstituted wood, having a thickness of not more than 14 mm; (II) a single resilient layer having a thickness of not more than 10 mm secured or securable to one surface of said substrate; (III) the resilient layer being secured or securable on its opposite surface to said floor or other integer. The arrangement is such that in use the securing together of the substrate and the resilient layer and the securing of the resilient layer to the floor or other integer provides a reduction of sound transmission through the floor or other integer. A method of reducing sound transmission is also disclosed.

TECHNICAL FIELD

The present invention relates to sound transmission reduction inbuilding constructions and particularly but not exclusively to soundtransmission through concrete floors.

BACKGROUND ART

For simplicity the present invention will be described in the context ofits use with a concrete floor. It is to be understood, however, that thepresent invention would have application wherever control of soundtransmission, particularly structure-borne sound transmission, through asolid floor or even wall of any material was required.

In apartment blocks and other close proximity residential dwellingsthere is a recognised need for effective sound proofing between roomsand between dwellings. This is of increasing importance, at least in NewZealand and Australia, as occupant expectations and building coderequirements increase.

A particular problem is in respect of relatively low frequency, and inthe case of hard floor surfaces high frequency, sound transmissionthrough the floors of a building.

A known method of reducing interfloor sound transmission involves theuse of a relatively thick resilient layer, often rubber, beneath thefloor covering. However, previous systems all suffer from disadvantagesrelating to their total thickness, acoustic performance and/orsuitability for use with all common types of floor coverings. Inparticular some of the prior art systems are unsuitable for use withrelatively rigid and brittle coverings such as ceramic tiles.

Australian patent AU 403,047 describes a laminate comprising apolyvinylaromatic resin bonded to a wood chip board upper layer. Suchchip board may provide an unsuitable surface for many floor coverings,including ceramic tiles or vinyl. Even if a further layer is addedbetween the chip board layer and the tiles, the chip board may require asurface treatment and/or a further stabilisation layer to be added,which may increase the cost and the time required for installation.

International publication WO 98/21027 describes a sound absorbingresilient layer comprising a rubber underlay, preferably manufacturedfrom recycled tyres, with a grooved lower surface. The resilient layeris preferably between 11/64″ (˜4.4 mm) and 3″ (˜76 mm), and mostpreferably between ⅜″ (˜9.5 mm) and 1″ (˜25.4 mm). The grooves in theresilient layer are intended to enhance the sound attenuating propertiesof the resilient layer by limiting the contact area with the sub-floor.

This system, particularly in its more preferred form, may be relativelythick. This may be undesirable as the total height of each living spaceincorporating the resilient layer must be increased to ensure thatregulations regarding ceiling to floor spacing are complied with. Thismay increase the cost of buildings such as multi-story apartment blocks.Where a maximum building envelope limit is imposed, thicker overlays canreduce the number of levels for rent. From an occupant and designerperspective, there is often resistance to thicker overlays because asmall step results where the thick overlay is installed beneath hardsurfaces, but not beneath carpet. This may result in unsatisfactoryaesthetics and may compromise safety.

U.S. Pat. No. 5,968,630 describes a laminate which includes acombination of a low density polyethylene foam and low densitypolyethylene film which is loose laid on a concrete sub-floor. A woodenlaminate flooring is installed over the polyethylene layers. The systemis intended to help smooth irregularities in the sub-floor and tointroduce a measure of resilience to the floor as a whole.

One problem with this system may be that the upper layer may be tooflexible to allow rigid floor coverings such as ceramic tiles to be usedwithout a risk of cracking, and may therefore only be suitable forflexible floor coverings such a vinyl or rubber tiles. The flexiblefloor may lack a solid feel which many people may prefer. The foam mayalso compress locally under high pressure loading, such as that providedby some furniture, thereby reducing the acoustic performance of thesystem. Even if the foam is not compressed in this way, the acousticperformance of the system may not be sufficient for some applications.

EP 864,712 describes a simple sound rubber mat which reduces the noiseproduced by an upper timber floor. This system may suffer from theproblems associated with a lack of rigidity common to systems which usea timber upper surface, as described above.

EP 829,588 describes a board suitable for covering a floor or wall whichis manufactured from a mixture of rubber scrap and expanded polystyrene.

Other systems of the prior art have involved pouring an upper layer of asettable substance on top of a resilient layer, the upper layer settingto provide a relatively stiff substrate on top of the resilient layer.Systems of this type may be inconvenient to install and in particularmay slow the progress of the construction while the upper layer cures.

None of the systems described above combine the characteristics ofacceptable noise attenuation, easy installation, ability to cope withsustained in-use serviceability loads, relatively low overall thicknessand broad compatibility with most common flooring surfaces.

The Applicant does not concede that any or all of the patents referredto above necessarily form part of the common general knowledge of askilled addressee, or are necessarily patents which would be discoveredby a diligent searcher.

OBJECTS OF THE INVENTION

It is therefore an object of the present invention to provide a soundtransmission reduction system for a building construction which providesa cost effective and relatively thin and user friendly soundtransmission control which overcomes or at least amelioratesdisadvantages of present proposals or which at least will provide thepublic with a useful choice.

Further objects of the invention will become apparent from the followingdescription.

DISCLOSURE OF THE INVENTION

According to one aspect of the present invention there is provided asound transmission reduction system for use between a floor or otherinteger of a building construction and a suitable covering for saidfloor or other integer includes;

-   -   a rigid single layer substrate of gypsum fibreboard, fibre        cement, hardboard, plywood or stabilised reconstituted wood,        having a thickness of not more than 14 mm;    -   a single resilient layer having a thickness of not more than 10        mm secured or securable to one surface of said substrate;    -   said resilient layer being secured or securable on its opposite        surface to said floor or other integer, the arrangement being        such that in use the securing together of said substrate and        said resilient layer and the securing of said resilient layer to        said floor or other integer provides a reduction of sound        transmission through said floor or other integer.

Preferably, said substrate may be between 4 mm and 14 mm thick.

Preferably, said substrate may be between 6 mm thick and 14 mm thick.

Preferably, said substrate may be substantially 6.5 mm thick.

Preferably, said substrate may have a modulus of elasticity of between 3GPa and 18 GPa.

Preferably, said substrate may have a modulus of elasticity ofsubstantially 7 GPa.

Preferably, said substrate may have a modulus of rupture of between 5MPa and 25 MPa.

Preferably, said substrate may have a modulus of rupture ofsubstantially 11 MPa.

Preferably, said resilient material may be between 2 mm and 10 mm thick.

Preferably, said resilient material may be between 2 mm and 3 mm thick.

Preferably, said resilient material may be substantially 3 mm thick.

Preferably, said resilient layer may have a density of between 20 kg/m³and 150 kg/m³.

Preferably, said resilient layer may have a density of substantially 75kg/m³.

Preferably, said resilient layer may be a polyolefin.

Preferably, said resilient layer may be a foamed polyethylene.

Preferably, said substrate may be gypsum fibreboard.

Preferably, the total thickness of said system may be less than 11 mm.

Preferably, said sound transmission reduction system may have a pointload failure test result, as herein defined, of at least 1.5 kN.

Preferably, said sound transmission reduction system may have a pointload failure test result, as herein defined, of at least 1.8 kN.

Preferably, said substrate may include a plurality of sheets, withadjacent edges of said sheets glued together to form butt joints.

According to a second aspect of the present invention a method ofreducing sound transmission through a floor or other integer of abuilding construction includes:

-   -   securing one side of a single resilient layer having a thickness        of not more than 10 mm to said floor or other integer;    -   securing a single substrate of gypsum fibreboard, fibre cement,        hard board plywood or stabilised reconstituted wood, of        thickness not more than 14 mm, to an opposite side of said        single resilient layer;    -   wherein the resilient layer is secured to said substrate and        said floor or other integer such that sound transmission through        said floor or other integer is reduced.

Preferably, the method may include the step of securing a suitablecovering to said substrate on an opposite side to said resilient layer.

Preferably, the method may include the step of securing said singleresilient layer to said floor or other integer by means of a contactadhesive.

Preferably, the method may include the step of securing said substrateto said single resilient layer by means of a contact adhesive.

Preferably, said resilient material may be a polyolefin.

Preferably, said resilient material may be a foamed polyethylene.

Preferably, said substrate may be formed by a plurality of sheets ofgypsum fibreboard, fibre cement or hard board, the method including thestep of gluing adjacent edges of said sheets together to form buttjoints.

Preferably, said substrate may be gypsum fibreboard.

According to a further aspect of the present invention a soundtransmission reduction system and/or a method of reducing soundtransmission is substantially as herein described with reference to FIG.1 or FIG. 2.

Further aspects of this invention which should be considered in all itsnovel aspects will become apparent from the following description givenby way of example and with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: shows very diagrammatically a cross-sectional view through onepossible embodiment of the invention;

FIG. 2: shows very diagrammatically a cross-sectional view through ajoint in the embodiment of FIG. 1;

FIG. 3: shows a graph of the performance of the present inventioncompared to a bare concrete slab;

FIGS. 4 & 5: show graphs of the performance of the present inventioncompared with presently available floor coverings across a range offrequency;

FIG. 6: shows a comparison of the present invention with other availablefloor coverings in respect of its impact insulation class (IIC).

FIG. 7: shows a graph comparing the point load failure of the presentinvention with other available systems.

BEST MODE FOR CARRYING OUT THE INVENTION

In controlling sound transmission of noise within and between multi-unitdwellings the impact insulation class (IIC) rating is of particularsignificance. Many such dwellings will have concrete floors, and theneed to reduce impact sound transmitted through such floors is ofparticular concern. Typical solutions to date have utilised multiplelayers of various materials such as gypsum fibre and plywood, typicallywith the joints within the multi-layer system being staggered in orderto provide additional strength. Other solutions have incorporated thicklayers of a resilient material such as glass wool or mineral wood mattypically being loose laid over a floor and relying on dead weight forplacement. It will be appreciated that typically such present solutionshave tended to be at least 30 mm thick, usually more.

Other solutions such as the use of shredded rubber mats or bitumen basedmats have proved to be expensive and/or not installer-friendly. Incontrast the present invention due to its use of materials is expectedto be substantially less costly while also being installer-friendly.

Referring to the accompanying drawings and initially to FIGS. 1 and 2 anembodiment of the present invention is shown very diagrammatically incross-section and including in FIG. 2 the join between substrate sheets.

In the sound transmission reduction system of the present invention asshown and referenced generally by arrow 1, a single layer sheet materialsubstrate 2 is provided, on which a suitable floor covering (not shown),for example ceramic floor tiles, vinyl, timber or any other suitablefloor covering such as are well know to those skilled in the art, may belaid.

The substrate 2 is not more than 14 mm thick, or preferably 4 mm to 14mm thick and suitably 6.5 mm thick gypsum fibreboard, although othersuitably light, strong, rigid and dimensionally stable materials such asfibre cement, hard board, plywood, stabilised reconstituted wood or thelike may be used. Some of these substrates 2, for example plywood, maybe sufficiently hard wearing to allow the use of paint or polyurethaneas a floor covering in areas which are not subject to high traffic.

Preferably the substrate may provide a Modulus of Elasticity of 3 Gpa to18 Gpa and a Modulus of Rupture of between 5 Mpa to 25 Mpa, and morepreferably a Modulus of Elasticity of substantially 7 GPa and a Modulusof Rupture of substantially 11 MPa.

An under surface of the substrate 2 is shown secured with a resilientlayer 3. Suitably this securement is by means of a layer of adhesive 4.Such adhesive 4 may be provided across substantially all or merely partof the adjacent surfaces of the substrate 2 and the resilient layer 3 ormay be by spot adhesive. The adhesive layer 4 may suitably be a contactadhesive suitably with a less than 24 hour dry time. The suitableadhesive may for example, be Bostik (trademark) 1181 contact adhesive.

Installers of the system may prefer to use gypsum fibreboard as thesubstrate 2 due to the ease with which its dimensions may be varied onsite, suitably by the “score and snap” method, by which a sharp blade ispressed firmly and run across the face of the substrate 2, and resilientlayer 3 if already adhered to the substrate 2, to cut the resilientlayer 3 and score the substrate 2. The edges of the substrate 2 furthestfrom either side of the cut are then brought together to snap thesubstrate 2 into two pieces.

Gypsum fibreboard may also be manufactured in suitable size sheets,typically in the order of 1800 mm×1200 mm, which an installer may findparticularly convenient as they are of such a size, shape and weightthat they may be carried by a single person.

Gypsum fibreboard may also provide a suitable mounting surface for mostcommon floor coverings, and in particular for rigid floor coverings suchas ceramic tiles. Installation of the floor covering over gypsumfibreboard may be assisted by the fact that, due to the stiffness of thesystem, relatively shallow contours in the floor may be smoothed overrather than the substrate 2 following the contour of the floor as mayoccur in some systems of the prior art. This may improve the appearanceof the floor covering. In addition the gypsum fibreboard may provide apre-sealed surface onto which a suitable floor covering such as tilesmay be affixed without further preparation of the surface.

Those skilled in the art will appreciate that some of the advantagesmentioned above may also be provided by one of the alternativesubstrates 2 listed above.

The resilient layer 3 is relatively thin, not more than 10 mm thick, andpreferably towards the lower end of that range, suitably of the order of3 mm thick. Suitably the resilient layer 3 may be a polyolefin with highresilience and with sufficiently low creep and with suitably highcompressive strength. Preferably the characteristics of the resilientmaterial 3 would incorporate:

-   -   Approximately less than 10% creep at 23° C. in three years under        a 5 kPa load.    -   Approximate water absorption ASTMC-272-53 less than 0.5% by        volume absorption after total immersion in water for 24 hours.    -   Density of 20 to 150 kg/m³.    -   Thickness of between 2 to 10 mm.    -   Compressive strength greater than 2 kPa, or more preferably        compressive strength at 50% compression of 1.5 kPa.

A suitable material may be a 3 mm layer of foamed polyethylene.

The resilient layer 3 is shown secured to a floor 5, in this exampleillustrated as a concrete floor.

The securement of the resilient layer 3 to the floor 5 is by means of afurther adhesive layer 6. Suitably the adhesive layer 6 utilises a waterbased trowellable adhesive with a short dry time, preferably less than 1hour. Almost any suitable adhesive layer 6 may be used, such as urethanefor example. The Applicant has found that the choice of adhesive 6 doesnot impact on the acoustic performance of the invention provided theadhesive layer 6 is reasonably thin.

An important part of the present invention is the combination of arelatively thin resilient layer 3 with a suitably thin substrate 2. Ifthe resilient layer selected is too thick and/or of insufficient densityand/or of insufficient compressive strength, then the resilient layer 3may not provide sufficient support to the substrate 2 to accommodate inservice loads. Additionally, an improper resilient layer 3 may result inthe substrate 2 flexing sufficiently that cracking of floor coveringssuch as tiles, or telegraphing of imperfections to a vinyl surface, mayoccur. Deformation of the resilient layer 3 under localised loads mayalso significantly reduce the acoustic performance of the system.

Surprisingly however, the Applicant has found that a combination of asuitably dense, suitably thin resilient layer 3 with a suitablesubstrate 2 not only provides good serviceability, including sufficientstrength, rigidity, dimensional stability and flatness, but alsoexcellent impact sound insulation characteristics.

Referring briefly to FIG. 2, where sheets of the substrate 2 need to bejoined a high strength multi-purpose construction adhesive joint,suitably with less than 24 hour dry time and with water resistance, isprovided along the adjoining edges of the sheet 2 to create a butt typejoint. The joint 7 between the sheets 2 ensures that vertical loads aretransferred across the substrate 2 and is also effective at helping toprevent the telegraphing of cracks across the substrate 2. The abilityof the system to perform adequately with the joints 7 glued in this wayavoids the need to use double layers of substrate 2 with overlappingjoints, such as are common in the systems of the prior art. This maycontribute to the ease and speed of installation of the system as wellas keeping the overall thickness of the system to a minimum.

In view of the thickness of presently available solutions to the impactsound transmission problem, and in particular the thickness of some ofthe resilient layers of the prior art, and the choice of materials used,it would be expected that the present invention as shown in FIGS. 1 and2 would not provide adequate impact sound transmission control, or atleast would not perform as well as currently available systems.

It has been unexpectedly found in tests carried out on the presentinvention that it in fact performs better than most currently availableand more expensive systems of similar thickness and may perform betterthan many thicker systems of the prior art, while in many cases offeringa simpler construction.

Referring therefore to FIG. 3 the graph shows the performance of thepresent invention, referred to herein as the GIB® sound barrier boardconcrete system or abbreviated as GSBC, as compared to a bare concreteslab with no ceiling.

The sample tested used a 3 mm resilient polyethylene layer adhered to aconcrete surface by a layer of adhesive. The layer of adhesive, around0.5 mm-1 mm thick, was applied by a 3 mm deep notched trowel. Theresilient layer was pressed onto the adhesive. A sheet of 6.5 mm gypsumfibreboard was adhered to the upper surface of the polyethylene layervia a layer of adhesive of less than about 0.2 mm, thereby providing asound transmission reduction system of around 10.5 mm total thickness.

300 mm×300 mm ceramic tiles were adhered to the substrate with latexmodified cementitious adhesive. The tiles were spaced 3 mm apart, withthe gaps grouted.

It would seem that substantial impact sound control is provided at allfrequencies with the exception of the region around 500 Hz, whereresonance of the system appears to occur. Those skilled in the art willappreciate that all overlay systems may suffer from such a resonanceeffect at some frequencies.

Turning then to FIGS. 4 and 5, the test sample of the present inventiondescribed above is compared with presently available systems utilising abitumen-based mat and 5 mm and 10 mm shredded rubber mats. It wouldappear that the present invention performs well across the range offrequencies and better than the alternatives for some of thefrequencies.

Then in FIG. 6 the present invention (GSBC) is compared with the rubbermat alternative systems as far as its IIC rating is concerned and it isseen to be higher than either of the alternatives.

Acoustic testing of one sample which had a 3 mm resilient layer 3 with adensity of 75 kg/m³, a 6.5 mm gypsum fibreboard substrate 2, and coveredby a monocottura tiles provided a ΔLnw of 18 dB (or ΔIIC of 20 dB whentested to ISO 140-8:1997.

FIG. 7 shows point load failure results for the present invention and anumber of systems of the prior art, each with two different tiles ontheir upper surface. All references herein to point load failure testresults are with respect to tests carried out as described below withmonocottura tiles having a Modulus of Rupture of 40 MPa.

The embodiment of the present invention tested used a 3 mm resilientlayer and 6.5 mm substrate. The examples of the prior art included an 11mm thick bitumen mat, 5 mm thick shredded rubber mat, 5.5 mm thickshredded rubber mat and 5.1 mm thick bed of trowel-on acoustic adhesive.

The test samples were prepared as follows.

Two 300 mm×300 mm pieces of acoustic overlay were adhered to a concretesubstrate using an adhesive specified by the manufacturer of theoverlay. The pieces of overlay were butt-jointed as per themanufacturers recommendations, with the exception of the acousticadhesive which has no join.

One monocottura 300×300×8 mm tile and one 300×300×8 mm porcelain tilewere adhered to each overlay using a premium latex modified cementitioustile adhesive. The adhesive was applied along the length of the samplesusing a 8 mm×8 mm notched trowel angled at 45° to the surface. The tileswere set with a 3 mm gap. The gap was filled with flexible sealant. Thetile gap and acoustic overlay joins were aligned on each sample exceptthe bitumen mat, where the tiles were laid to the manufacturersspecifications of offsetting the overlay 450 to the tiled surface.

The monocottura tiles had nominal 2.2% water absorption and Modulus ofRupture of 40 MPa. The porcelain tiles had less than 0.2% waterabsorption and Modulus of Rupture of 54 MPA.

The specimens were allowed to cure for 11 days prior to testing.

The samples were loose laid on the base of an Instron (Trade Mark)universal testing machine. A 25 mm diameter steel ball bearing waspressed onto the surface of the tiles at two points, at a distance ofapproximately 4 mm from the sealant and 100 mm from the outer edges ofeach tile.

The load cell was advanced towards the tiles at a rate of 4 mm/minute.Failure was registered as the load at which the tiling system was heardto crack, although a physical crack in the tile was not necessarilyvisible.

As FIG. 7 shows, the present invention provided a superior point loadfailure strength of all the samples tested. The point load failure testdescribed above provides results which are representative of in-useserviceability, a higher test result indicating a better in-useserviceability.

A preferred embodiment of the present invention may provide a point loadfailure test result of at least 1.5 kN, or more preferably at least 1.8kN, under the test conditions described above.

It is thus seen that a single relatively thin substrate of gypsumfibreboard or the like, and a relatively thin layer of a resilientmaterial such as foam polyethylene secured together and with theresilient layer secured to the floor of a building, can surprisinglyprovide excellent impact sound transmission solution and provide anin-use serviceability load when covered with a typical floor coveringsuch as ceramic tiles. In that regard it would not be expected that asingle thin substrate on a resilient material would sustain in-useserviceability loads when covered with ceramic tiles, due to not beingstrong enough. However, testing of the present invention has shown it toperform well in that regard.

It is considered that the rigid substrate 2 is providing an effectiveload spreading across the surface of the resilient layer 3. In this waythe superior point load strength is being achieved. In a practicalsituation this would mean that a heavy item of furniture such as a tablewould not over time damage the resilient layer 3, in turn damaging itssound control characteristics, as could otherwise happen in previoussystems.

Where in the foregoing description, reference has been made to specificcomponents or integers having known equivalents, then such equivalentsare incorporated herein as if individually set forth.

Although the above description has been given by way of example withreference to possible embodiments of the invention, it is to beunderstood that modifications or improvements may be made withoutdeparting from the scope of the appended claims.

1. A sound transmission reduction system suitable for use between afloor or other integer of a building construction and a suitablecovering for said floor or other integer including: a rigid single layersubstrate of gypsum fibreboard, fibre cement, hardboard, plywood orstabilised reconstituted wood, having a thickness of not more than 14 mmand a modulus of elasticity of between 3 GPa and 18 GPa; a singleresilient layer having a thickness of not more than 10 mm secured orsecurable to one surface of said substrate; said resilient layer beingsecured or securable on its opposite surface to said floor or otherinteger, the arrangement being such that in use the securing together ofsaid substrate and said resilient layer and the securing of saidresilient layer to said floor or other integer provides a reduction ofsound transmission through said floor or other integer.
 2. The soundtransmission reduction system of claim 1 wherein said substrate isbetween 4 mm and 14 mm thick.
 3. The sound transmission reduction systemof claim 2 wherein said substrate is between 6 mm thick and 14 mm thick.4. The sound transmission reduction system of claim 3 wherein saidsubstrate is substantially 6.5 mm thick.
 5. (canceled)
 6. The soundtransmission reduction system of claim 1 wherein said substrate has amodulus of elasticity of substantially 7 GPa.
 7. The sound transmissionreduction system of claim 1 wherein said substrate has a modulus ofrupture of between 5 MPa and 25 MPa.
 8. The sound transmission reductionsystem of claim 7 wherein said substrate has a modulus of rupture ofsubstantially 11 MPa.
 9. The sound transmission reduction system ofclaim 1 wherein said resilient material is between 2 mm and 10 mm thick.10. The sound transmission reduction system of claim 9 wherein saidresilient material is between 2 mm and 3 mm thick.
 11. The soundtransmission reduction system of claim 10 said resilient material issubstantially 3 mm thick.
 12. The sound transmission reduction system ofclaim 1 wherein the resilient layer has a density of between 20 kg/m³and 150 kg/m³.
 13. The sound transmission reduction system of claim 12wherein said resilient layer has a density of substantially 75 kg/m³.14. The sound transmission reduction system of claim 1 wherein saidresilient layer is a polyolefin.
 15. The sound transmission reductionsystem of claim 14 wherein said resilient layer is foamed polyethylene.16. The sound transmission reduction system of claim 1 wherein saidsubstrate is gypsum fibreboard.
 17. The sound transmission reductionsystem of claim 1 wherein the total thickness of said system is lessthan 11 mm.
 18. The sound transmission reduction system of claim 1 witha point load failure test result, as herein defined, of at least 1.5 kN.19. The sound transmission reduction system of claim 18 with a pointload failure test result, as herein defined, of at least 1.8 kN.
 20. Thesound transmission reduction system of claim 1 wherein said substrateincludes a plurality of sheets, with adjacent edges of said sheets gluedtogether to form butt joints.
 21. A method of reducing soundtransmission through a floor or other integer of a building constructionincluding: securing one side of a single resilient layer having athickness of not more than 10 mm to said floor or other integer;securing a single substrate of gypsum fibreboard, fibre cement, hardboard plywood or stabilised reconstituted wood, of thickness not morethan 14 mm, and having a modulus of elasticity of between 3 GPa and 18GPa, to an opposite side of said single resilient layer; wherein theresilient layer is secured to said substrate and said floor or otherinteger such that sound transmission through said floor or other integeris reduced.
 22. The method of claim 21 including the step of securing asuitable covering to said substrate on an opposite side to saidresilient layer.
 23. The method of claim 21 including the step ofsecuring said single resilient layer to said floor or other integer bymeans of a contact adhesive.
 24. The method of claim 21 including thestep of securing said substrate to said single resilient layer by meansof a contact adhesive.
 25. The method of claim 21 wherein said resilientmaterial is a polyolefin.
 26. The method of claim 25 wherein saidresilient material is a foamed polyethylene.
 27. The method of claim 21wherein said substrate is formed by a plurality of sheets of gypsumfibreboard, fibre cement or hard board, the method including the step ofgluing adjacent edges of said sheets together to form butt joints. 28.The method of claim 21 wherein said substrate is gypsum fibreboard. 29.(canceled)
 30. A sound transmission reduction system suitable for usebetween a floor or other integer of a building construction and asuitable covering for said floor or other integer including: a rigidsingle layer substrate of gypsum fibreboard, fibre cement, hardboard,plywood or stabilised reconstituted wood, having a modulus of elasticityof between 3 GPa and 18 GPa; a single resilient layer secured orsecurable to one surface of said substrate, the total thickness of saidsubstrate layer and said resilient layer being less than 11 mm; saidresilient layer being secured or securable on its opposite surface tosaid floor or other integer, the arrangement being such that in use thesecuring together of said substrate and said resilient layer and thesecuring of said resilient layer to said floor or other integer providesa reduction of sound transmission through said floor or other integer,and wherein the system has a point load failure test result, as hereindefined, of at least 1.5 kN.